These were designated in two phases after a process closely involving stakeholders. The first 27 zones were designated on 21 November 2013. Following consultation, 23 sites in the second phase were announced on 17 January 2016, bringing the total area protected to 7,886 square miles. Updated GIS data for all designated MCZs has been published.

A third phase will be consulted on in 2017, and designated in 2018. The third phase will aim to complete the UK Blue Belt and our contribution to the ecologically coherent network in the North East Atlantic.